Various types of mailers with windows are in common use. Typically, the window consists of a die cut opening in a mailer panel which permits addressee information inside the mailer to be read. The opening may be covered with a transparent patch, secured in placeover the cut out opening by means of an adhesive. The transparent patch may consist of any suitable film of transparent material such as glassine, cellophane, or polymeric materials. The adhesive is generally applied to the mailer substrate around the perimeter of the die cut opening to join the outer perimeter of the transparent patch to the substrate. The transparent patch can be adhesively secured to either the inside surface or the outside surface of the mailer substrate. The transparent patch insures that the contents of the mailer remain in the mailer.
In some modern mailing systems, a mailer is formed from a single sheet after it has been imaged by a nonimpact printer. The sheets are stacked in an input tray and fed individually as single plies through the printer, after which the sheets are each folded to form a mailer. The name and address of the addressee are printed on an interior panel of the mailer, but are viewed through the window after the mailer has been folded.
One difficulty encountered in using mailers that have transparent window patches is that the added thickness of the sheets caused by such window patches over the die-cut window openings causes uneven stacks in the input and output trays. Additionally, transparent patches covering die-cut window openings may also snag on equipment or on other mailers as the mailers are fed and folded, resulting in mis-feeding and jamming of equipment. This usually results in the destruction of one or more mailers and requires that the machinery be stopped so that the destroyed mailers can be removed. Further, since such mailers are individually created and addressed, it is necessary to determine the addressee of each destroyed mailer, so that substitute mailers can be printed.
Other mailers include windows that are formed by the application of transparentizing coating material to a portion of a mailer panel. Such a mailer is disclosed in U.S. Pat. No. 5,418,205, issued May 23, 1995, to Mehta et al., and assigned to the assignee of the present application. While a mailer with a transparentized portion forming the mailer window avoids problems associated with window patches, such a mailer may not be totally transparent, but may require that the transparentized window be in close proximity to the address information for optimum readability.
Other mailers use an uncovered window, simply defined by a die cut opening. While this results in a mailer in which sheet feeding is improved and addresses are easily read, it also produces a mailer envelope which is not completely sealed. Such an envelope may permit additional information, inside the mailer to the side of the address information, to be read. In fact, window mailers having transparent patches are also subject to undesirable viewing of the mailer contents by moving the window away from the address panel to permit other printed information with the mailer to be seen.
It is seen that there is a need for a mailer construction having a window arrangement that does not hinder printing and folding operations. Further, there is a need for a mailer in which the security of the mailer contents is enhanced.